Heel trimming machines



Feb. 5, 1957 B. J. M. MURPHY ET AL 2,779,957

HEEL TRIMMING MACHINES 4 Sheets-Sheet 1 Filed May 25, 1955 llllilllllllllllllll [n 0812 fora Brian JMMurphy John Pope Feb. 5, 1957 B.J. M. MURPHY ET AL 2,

HEEL. TRIMMING MACHINES Filed May 25, 1955 4 Sheets-Sheet 2 'lnvcmorsBman JM/furphy John ,5 Pope Feb. 5, 1957 r B. J. M. MURPHY E AL2,779,957

HEEL TRIMMING MACHINES Filed May 25, 1955 4 Sheets-Sheet 3 fig. 7 (9 E wJ E f fix Fig. 8

5 John R Pope J96 36 r By 13% may Feb. 5, 1957 B. J. M. MURPHY ET AL2,779,957

HEEL TRIMMING MACHINES Filed May 25, 1955 4 Sheets-Sheet 4 InventoryBrian JMMJrp/ y John RPope United States Patent HEEL 'IRIMMING MACHINESBrian Julian Maurice Murphy and .iohn Rose Pope, Leicester, England,assignors to United Shoe Machinery Corporation, Flemington, N. J., acorporation of New Jersey Application May 23, 1955, Serial No. 510,426Claims priority, application Great Britain June 29, 1954 Claims. (Cl.12-88) This invention relates to machines for trimming portions ofpartially fabricated shoes and more particularly to a heel trimmingmachine of the type disclosed in United States Letters Patent No.961,752, granted June 21, 1910, on an application filed in the name ofJ. N. Bnsell. The Bnsell machine is provided with a pair of curvedcutter blades removably clamped in a cutter head. The blades areadjustable radially of the axis of rotation of the cutter head, along apair of eccentric ribs which fit mating grooves in each of the blades,by an adjustable rotatable plate which engages the rear ends of theblades. This mechanism is generally satisfactory provided the blades area well matched pair. Should, however, one blade be shorter than theother, for example through unequal sharpening, it will project from thehead less than the other and will not do its fair share of the trimming.Furthermore, once the blades have been sharpened, even if doneuniformly, it requires a time consuming trial and error adjustment ofthe totatable plate to locate their cutting edges at the same distancefrom the axis as they were before sharpening, which is important inprecise shoemaking.

An object of this invention is to provide a heel trimming machine havinga plurality of interchangeable cutting blades, the cutting edges ofwhich are always rotatable in a single circular path.

Another object of this invention is to provide a heel trimming machinehaving easily removable cutting blades in a cutter head and convenientmeans for accurately positioning the cutting edges of each bladeequidistant from the axis of rotation of the cutter head regardless ofthe lengths of the blades which vary according to the extent ofsharpening of the individual blades or the angles at which the cuttingfaces are ground.

In accordance with these objects and as a feature of this invention thetrimming machine herein illustrated is provided with a cutter headcomprising a pair of ribbed clamping members between which cuttingblades are removably secured, one of the clamping members housing a pairof diametrically opposed positioning stops, each stop being engageablewith the cutting edge of one blade, the stops being operative when themachine is at rest and automatically retractable out of engagement withthe cutting edges when the head is rotated. By positioning the blades inthe cutter head by mechanism such as stops which control the location oftheir cutting edges rather than their rearward ends as in the priormachines, the cutting edges are equidistant from the axis of rotationand when rotated both cutting edges move in the same path and equallyshare the task of trimming a heel. Furthermore, with this mechanism,blades need no longer be of matched pairs and the angle of their cuttingfaces need not be exact. Also, one blade may be replaced withoutreplacing its mate. Likewise, blades of varying width designed for useon different height heels may be inserted in the machine with theircutting edges rotatable equidistant from the axis of the cutter 2,779,957 "Patented Feb. 5, 1957 head in the same circular path as bladesof any other size or width.

The above and other features of the invention, including novel detailsof construction and combinations of parts, will now be described withreference to the accompanying drawings and pointed out in the claims.

In the drawings,

Fig. l is a front elevation partly in section of the operating portionofone form of machine embodying the invention;

Fig. 2 is a plan view partly in section of the part of the machine shownin Fig. 1 with the cutting head assembly removed;

Fig. 3 is a detail view in elevation and partly in sec tion of a cutterblade positioning means having stop members against which the cuttingedges of the blades are positioned, the stop members being in retractedposition;

Fig. 4 is a view similar to Fig. 3 but with the stop members extended toa position in which the cutting edges may be placedagainst them;

Fig. 5 is a front elevation, partly in section, of the cutter bladepositioning means showing the stop members in retracted positions;

Fig. 6 is a View similar to Fig. 5 but with the stop members extended topositions in which the cutting edges may be placed against them;

Figs. 7 and 8 are detail views in elevation and partly in section of themechanism for advancing and retracting the stop members, Fig. 7 showingthe mechanism in the position whereby the stops are retracted and Fig. 8whereby the stops are advanced; and

Fig. 9 is a diagrammatic representation of the shape of a crease guideviewed from the right of the machine in the position shown in Figs. 1and 2, but on an enlarged scale.

The heel trimming machine herein illustrated is generally similar inconstruction and method of operation to the machine disclosed in theaforementioned Bnsell Patent No. 961,752, and attention is directed tothat patent for the description of parts not hereinafter described indetail.

The machine has a cutter head assembly 2 (Fig. I) mounted in front of adust hood 3 on the left end of a driven cutter shaft 4, journaled in aframe 6. The cutter head comprises a ribbed hub member 8 fixed to theshaft 4 and a mushroom shaped ribbed member 10 fixed to a shaft 12 whichpasses through an axial bore in the cutter shaft 4. Threaded in theshaft 12 is a screw 14 which, when rotated in a clockwise direction,draws the ribbed member 10 toward the ribbed hub 8 to clamp a pair ofcutter blades 16 therebetween, eccentric ribs 18 (Figs. 5 and 6) formedon the opposed faces of the members 8 and 10 engaging mating groovesformed in the blades 16 acting as guideways for the blades. The ribs 13and the blades 16 are similar to the parts referred to as 10 and 12,respectively, in the above-mentioned patent to Busell, although the ribsmay be formed on the blades and the mating recesses in the members 8 andIt A keyway 20 formed in the shaft 12 engages a complementary key fixedin the cutter shaft 4 to prevent relative rotation of the ribbed members8 and 10.

Surrounding part of the ribbed hub member 8 is a top lift rest 22 andadjacent the blades 16 is a work rest 24. The top lift rest and the workrest respectively are similar in construction to the top lift rest 22and the work rest 42 described in the Bnsell patent. A crease guide orguard attachment 26 shrouds the mushroom-shaped member 10 and will bedescribed in detail hereinafter.

The ribbed member 8, best seen in Figs. 3 to 8, is hollow and ofcomposite construction, housing a pair of retractable stops 23. Thestops are located diametrically opposite each other on either side ofthe cutter shaft 4 (Figs. 5 and 6). Each stop has a finger portion 39that is arranged, when the cutter shaft is at rest, to protrude from thehub member 8 in position to be engaged by the cutting edge 32 of one ofthe blades 16. An operator places the cutting edge of each blade againstits respective stop by moving the blade along the eccentric r-ib 18. Theblades are then securely clamped by tightening the screw 14-. By thisconstruction, when the machine is started, the cutting edges 32 of bothblades are always rotated in a single path, the edges being locatedequidistant from the axis of rotation B of the cutter shaft regardlessof any difference in initial length of the blades or how much one ofthem has been ground, contrary to the machine of the Busell patent whichrequires perfectly matched blades at all times. It will be obvious thatif more than two blades are used an additional stop for each blade wouldbe provided and the stops spaced at equal angles around the cutter head.

Furthermore, when other size blades are inserted having, for example,different widths, their cutting edges will be rotated in the same singlepath equidistant from the axis B.

The retractable stops 28 are automatically withdrawn, by means new to bedescribed, within the ribbed hub member 8 and clear of the cutting edgesof the blades, when the cutter head is rotated. Each retractable stop 28lies in a longitudinal slot 34 (Figs. 5 and 6) formed in a cylindricalstud 3:6, and is pivoted on a pin 38 fixed in the stud. The left-handportions (Figs. 3 and 4) of the studs 36 slide in bores 40 formed in thehub member 8 parallel to the axis B of the cutter shaft 4, and therighthand ends of the studs are fixed in a ring 42, which lies withinthe hub member 8. A portion of the ring 4-2 embraces the cutter shaft 4(Figs. 7 and 8) and slides lengthwise of it, being kept from rotationrelative to the cutter shaft by the studs 36 engaging the bores 40.

The ring 42 is urged to the left (Fig. 4) by a pair of compressionsprings 44 housed in longitudinal bores 46 formed in the studs 36 and, v1 1 1655ed between the studs and a face 48 on the hub member 5. Movementof the ring 42 to the left, under the action of the springs 44, islimited by the engagement of a conical concave face 5t) formed on thering with a plurality of balls 52 which engage a circumferential groove54 (Figs. 7 and 8) formed in the cutter shaft 4 and a concave Conicalface 56 formed on the hub member 8. This plurality of balls 52 isdivided into two egual groups by the studs 36, each group occupying anequal portion of an annular cavity 58 (bounded by the cutter shaft 4,the hub member 8, and the ring 42).

Spring-biased plungers 6*?) (Figs. 3 and 4) housed the studs 36 engageabutments 62 formed on each of the retractable stops 28, and tend topivot the stops about the pins 38 in a direction to move the fingerportions 34 away from the axis B of the cutter shaft. Pivotal movementof each retractable stop 28 under the action of its spring plunger 60 islimited by the engagement of the stop with a cam face 64 (Fig. 3) formedon the ribbed member 8.

Thus, when the cutter head is at rest and the balls 52 are in thepositions shown in Figs. 6 and 8, the finger portions of the retractablestops 28 are held to the left, and outwardly away from the axis B of thecutter shaft, by the compression springs 44 and the spring-biasedplungers 60 respectively, so that they protrude from the hub member 8,see Figs. 4 and 6. As they so protrude, the cutting edges 32 of theblades 16 may be moved by the operator into engagement with them beforethe blades are clamped between the ribbed members 8 and 10 of the cutterhead 2 by the screw 14.

When the cutter shaft is rotated, the balls 52 are urged outward underthe, action of centrifugal force, and at a speed well below the normalrunning speed of the cutter head the balls move outward, away from thecircumferential groove 54 formed in the cutter shaft from the positionsin Fig. 8 into the positions shown in Fig. 7. As the balls move outwardthey force the conical faces 50 and 56 apart, moving the ring 42 to theright and thus withdrawing the retractable stops 28 within the hubmember 8. As the ring 42 moves to the right against the resistance ofthe springs 44 the cam faces 64 formed on the hub member 8 cam thefinger portions 3% of the retractable stops inward toward the axis B ofthe cutter shaft against the resistance of the spring-biased plungers60. Thus, before the cutter head reaches its cutting speed theretractable stops are automatically withdrawn clear of the cutting edges32.

Cooperating with the top lift rest 22 and the work rest 24 to supportand guide a shoe as its heel is presented to the cutting head is thecrease guide 26 which shrouds the mushroom-shaped member 19 (Fig. 1).The crease guide is in the form of a dished plate having a stud 70 fixedto its convex surface, the center of which stud lies on an axis C. Thework engaging portion of the periphery of the crease guide is in theform of an involute and will be more fully described hereinafter. Thestud 70 is supported in a bore in the enlarged right-hand end of a slide72, and is restrained from axial movement by a pin 74 (Fig. l) fixed inthe slide and engaging a groove 76 (Fig. 2) formed in the stud andextending part way around its periphery. In order to adjust the workengaging portion of the crease guide relative to the cutting blades 16as will be explained in more detail hereinafter, the creases guide isrotated on its axis C relative to the slide 72 but this movement islimited by the pin 74 engaging the cnd of the groove 76. A clamp screw78 threaded in the slide engages the stud to enable an operator to lockthe crease guide in a desired angular position. Graduations 73 marked onthe crease guide assist the operator in selecting the angular position.

The main portion of the slide 72 which is cylindrical and coaxial withthe stud 70 is axially adjustable in a carrier 80, in a mannerhereinafter to be described. A key 82 (Fig. l) fixed in the carrierengages a complementary ,keyway formed in the slide and thus preventsrotation of the slide relative to the carrier. The slide is adjustedaxially in the carrier by an adjusting screw 84', threaded in theleft-hand end of the slide, the screw having a knurled knob 86 and aflange 68 which engages a plate 94 fixed to the carrier. A spring 92compressed between the knurled knob 86 and the plate tends to preventbacklash developing in this mechanism and to prevent inadvertentrotation of the adjusting screw 34. Graduations (not shown)corresponding to different width cutter blades are marked on the slideto assist the operator in adjusting the crease guide to a desiredposition so that it just shrouds the ribbed member 16, as will be morefully explained hereinafter.

The carrier 80 is pivoted on a vertical stud 9.4 fixed in the forwardend of a link 96 the rearward end of which is fixed by means of a clampscrew 98 to a vertical pin 100 journaled in bearings 102 and, 104 in theframe 6. Extending rearwardly from the carrier St) is a flange 106having formed in it an arcuate slot 168. A link 110 is adjustablysecured to the flange 106 by means of a clamp bolt 112 passing throughthe arcuate slot and having an enlarged head 114- engaging the lowersurface of the flange. A wing nut 116 threaded on the bolt 112 enablesthe operator to clamp the link 110- in any position along the arcuateslot. Graduations 118 along the slot assist the operator in positioningthe link ilt) for a purpose to be explained hereinafter. The rearwardend of the link 110 is pivoted on an eccentric portion 129 of a bolt 122adjustably mounted in the frame 6 and secured thereto. by means of alock nut 123. The bolt 122 is in a position (see Fig. 2) forward and tothe left of the pin 100.

The carrier 80, and consequently the crease guide 26,

is urged to the right, as seen in Figs. 1 and 2, by means of a tensionspring 124 secured to the frame 6 and to an arm 126 fixed to the lowerend of the pin 100. Movement of the crease guide to the right under theaction of the spring 124 is limited by an adjustable stop screw 128threaded in the link 96 and held in adjusted position by a lock nut 130.The forward end of the stop screw abuts a portion of the frame 6.

The work rest 24 is supported by a cylindrical split bar 132 having twobranches 134 and 136 separated by a slot 138 which extends lengthwise ofthe split bar nearly to its rearward end. The split bar is supported ina horizontal bore 139 formed in the frame 6. The work rest 24 has acylindrical stem 140 which is gripped between an arcuate seat 142 formedin the branch 134 and an eccentric pin 144 journaled in the branch 136,the eccentric pin having a handle 146.

The construction and arrangement of the parts are such that by turningthe handle 146 the eccentric pin 144 binds the stem 14h forcing itagainst the seat 142. This single operation not only locks the stem 140in position relative to the split bar 132 but, by forcing the branches134 and 136 apart, also locks the split bar in the bore 139. Conversely,reverse movement of the handle 146 not only releases the stem 140 forsliding and rotating movement relative to the split bar 132 but alsoreleases the split bar for sliding and rotating movement relative to theframe 6.

Referring to Fig. 1, the dotted outline of a shoe is shown in positionto have its heel trimmed. The heel is supported on the work rest 24 withits top lift in engagement with the top lift rest 22. The crease guide26 engages the shoe in the crease between the heel and the upper whichis frequently called the rand crease. It will be noted that the distancefrom the top lift to the mud crease is greater at the rear of the heelthan at the front or heel breast. Therefore, as the shoe isturned by theoperator to present successive portions of the heel to the cutter, thecrease guide must yield to the left as the rear of the heel approachesit and then must return to the right as the second side of the heel istrimmed, the crease guide at all times being in engagement with the randcrease. The amount of movement is relatively slight and just equal tothe difference in the heel height from front to rear and varies,depending on the shoe size and style.

The arrangement of the links 96 and 110 supporting the carrier 86 andtheir associated mechanisms permit the crease guide to yield against theforce of the spring 124, the positions of the various above-mentionedadjustable members determining the path of movement as now to bedescribed. When the crease guide is in the position ready for use itshrouds the ribbed member the position of which, lengthwise of thecutter shaft 4, depends on the width of the cutters clamped in thecutter head. The cutters are selected to accommodate the height of aheel to be trimmed. In this position the axis C of the stud 70 liessubstantially parallel to the axis B of the cutter shaft 4 and a littlebelow it. The bolt 122 is rotated initially so that its eccentricportion 120 acting through the link iii) makes axes B and C parallel.The radius of the arcuate slot 108 is equal to the length betweencenters of the link 110; therefore any adjustment of the bolt 112 in theslot does not affect the parallelism of the axes.

Adjustment of the slide 72 in the carrier when the crease guide is inits starting position moves the crease guide lengthwise toward or awayfrom the ribbed memher 10, the cutter size graduations on the slide 70enabling the operator to set the crease guide in the appropriateposition for the particular pair of cutters being used. The stop screw128 is initially used to make the rough adjustment of the crease guiderelative to the cutters and the knurled knob 86 to make the fineadjustment.

By adjusting the bolt 112 in the slot 108 the operator determines thepath followed by the crease guide as it moves yieldingly away from thecutter head in accordance with the style of heel to be trimmed. The mostsuitable path to be followed for a particular style of heel isdetermined by trial and error, the slot graduations 118 assisting theoperator to obtain a setting shown by experience to be correct. When themachine is used to trim a low heel the yielding movement of the creaseguide is small and the setting of the bolt 112 relatively unimportant. V

The arrangement of the carrier 80, the links 96 and and their associatedmechanisms which provide for this path of movement is well known and isnot described in further detail.

Owing to the involute shape of its periphery, angular adjustment of thecrease guide 26 about the axis C of the stud 70 varies the distancebetween the axis of the cutter head B and that forward shoe engagingportion of the periphery of the crease guide which engages the creaseformed between the heel and the upper of the shoe. Therefore, angularadjustment of the crease guide 26 determines how close to the crease andthe upper the cutters trim the heel.

Fig. 9 is a diagrammatic representation of the shape of the crease guideas seen from the right side of the machine in the position shown inFigs. 1 and 2 when the crease guide is in starting position shroudingthe ribbed member 10. An intermediate portion A of the involute portionDAE of the periphery DAEFI of the crease guide 26 is shown turned intothe shoe engaging position, this shoe engaging position being in frontof and level with the cutter head axis B.

The involute portion DAE is generated by the end of a straight linerolling on a hypothetical circle I which has its center on the axis C ofthe stud 70 and passes through the axis B of the cutter shaft; thus, theradius of the circle I is equal to the distance between the axes B andC. It will be seen that the shoe engaging portion A of the crease guidelies approximately on the arc GH (shown as a dotted line) which isstruck about the axis B of the cutter shaft. Because of this and thefact that the cutting edges 32 of any pair of blades 16 are alwayspositioned equidistant from the axis B due to the use of the stops 28,the shoe will remain at a desired distance from the cutters should itengage the crease guide at a point somewhat above or below the axis B ofthe cutter shaft at any stage of the trimming operation even if theblades are changed before a heel is fully trimmed.

Since the crease guide is adjusted about the axis C and is required, inone position at least, to fit close to the ribbed member 10 (whichrotates about the axis B) it is necessary to limit the involute portionDAE to about two-fifths of the periphery of the crease guide, and tolimit angular movement of the crease guide (by means of the pin 74) toavoid contacting the ribbed member 10 in one position or another of thecrease guide.

Arcuate portions DI and EF of the periphery of the crease guide blendsmoothly with, and form continuations of, the involute portion DAE sincethey may engage the shoe, on occasion, should the operator cause theshoe to contact the crease guide at a point above or below the axis B ofthe cutter shaft, when the crease guide is set in an extreme angularposition.

Thus for any working angular position of the crease guide, the shoeengaging portion of its periphery lies approximately along an arc struckabout the axis B of the cutter head, thereby providing a working surfaceon which the shoe can be swung Without causing it to move appreciably,inwardly or outwardly, radially of the cutter head. Therefore, becausethe working portion of the crease guide is an involute rather than aseries of stepped arcs, as in the prior machines, the shoe may bepositioned with maximum accuracy at a desired distance from the axis ofthe cutter head and the path of the cutting blades. The operator maythus vary by any desired amount,

7 however small, the closeness with which thecutters, as they trim;theheel, approachthe-upper of the shoe:

The creasc i guide and its operating mechanism" formno part of thepresent invention but are claimed in a copendingdivisional= applicationSerial= No. 592,678, filed June 20, 19,56, in our names.

Having described our invention, what we claim as new and desire tosecure by Letters Patent of' the United States is:

1. In a heel trimming machine, a rotatable cutter head mounting a.plurality of cutting blades adjustable radially of its axis. ofrotation,and positioning means carried at all times by saidicutterheadandengageable with the blades to locate all of said cutting edges at pointsequidistant from said, axis. of: rotation irrespective of the length oftheblades or theangles of their cutting-faces.

2. true heel trirnming-machine; arotatable cutter head mountirraplurality of cuttingbladesadjustable radially of its axis of rotation,and positioning means carried at all times by said cutter head andengageable with the cutting edges of each blade to locate allof'saidcutting edges at points equidistant from saidaxis of rotation.

3. in a heel trimming machine having a rotatable cutter head, mounting aplurality of cutting blades adjustable radially. of. its axis ofrotation, positioning means carried by the cutter head and engageablewith the cutting edges of each blade when the cutter; head is at rest tolocate all of said, cutting edges at points equidistant from said axisof rotation irrespective of the length of the blades, and automaticretracting means operative to withdraw the positioning means fromengagement wtih the cutting edges in response to rotation of the cutterhead.

4. In a heel trimming machine having a rotatable cutter head mounting aplurality of cutting blades adjustable radially of itsaxis of rotation,positioning means carried by the cutter head and engageable with thecutting edges of each blade when the cutter head is at rest to locateall of said cutting edges at points equidistant from saidaxis ofrotation irrespective of the length of the blades, and automaticretracting means operative by centrifugal force inresponse to rotationof thecutter head to withdraw the positioning means, from engagementwith the cutting edges.

5. In a heel trimming machine having a rotatable cutter head mounting aplurality of curved cutting blades adjustable radially of its axis ofrotation along symmetrical eccentric guideways on the cutter head, aplurality of positioning stops angularly spaced equally around thecutter head and" associated one with each blade, means operable when thecutter head is: at rest to locate each L stop in a position wherein itis engageable with the cutting edge of its associated bladeto-loeate allof the cutting edges at points equidistant from the axis of rotation ofthe cutter head irrespective of the length of the blades, and meansoperative in response-to rotation of the cutter head to withdraw saidpositioning stops from engagement with said cutting edges.

6. In a heel trimming machine having a rotatable cutter head mounting aplurality of curved cutting blades adjustable radially of its axis ofrotation along symmetrical eccentric guideways on the cutter head, aplurality of positioning stops angularly'spaced-equally around thecutter head and associated one With-each blade, means operable when thecutter head is at" rest to locate each stop in a. position wherein it isengageable with the cutting edge of its associated blade to locate allof the cutting edges at.points.equidistantfrcm the axis of rotation ofthe cutter head irrespective ofthe length of the blades, and meansoperative by centrifugal force in response to rotation of the cutterhead to withdraw said positioning stops from engagement withsaidcuttingedges.

7. In a heel trimming machinehaying arotatablecutter head comprising apair of, axially spaced clamping members, a p r i y Q 1 d.. uttr,,b adesnemovablymount ed between said-clamping members; and adjustable. radial:

1y of the cutter-head along; symmetrical guidew aysformed eccentricallyto; its axis of rotation; a plurality of" positioning stops angularlyspaced" equally around one of said clamping members and associated onewith each blade, actuating means operable when the cutter head is atrest tol'ocate each stop in a position intersecting the path ofadjustmentof its associated blade and engageable with its cutting edgewhereby all of the cutting edges may beaccurately located at pointsequidistant from the axis of rotation of the cutter head irrespective ofthe length of the blades, and means operable in response to rotationofthe cutter head to withdraw said positioning stops from engagement withsaid cutting edges.

8. In a heel tr-imming-machinehaving a rotatable cutter head' comprisinga first clamping member mounted on a drive shaft, and a second clampingmember spaced from and movable axially toward said first clampingmember, a plurality of: curved" cutting blades removably mountedbetween. the clamping members and adjustable radially of the cutter-headalong symmetrical guidew ays formed on the clamping memberseccentrically to the axis of rotation of the cutter head, an annularring movable axially within the first clamping member, a plurality ofblade positioning members associated one with each blade and pivotallysecured to the annular ring at points angularly spaced equally from eachother, a finger portion on each positioning member engageable with thecutting edge of its associated blade, first resilient means for urgingsaid annular ring and positioning members axially of the cutter headtoward the blades, second resilient meansfor urging-the finger portionsradially of the cutter head into the path of adjustment of the blades tolimit their adjustment, whereby all of the cutting edges may beaccurately located at points equidistant from the axis of rotation ofthe cutter head, and retracting means operable in response to rotationof the-cutter head to withdraw the fingerportions from engagement withthe blades and retract the positioning members within the first clampingmember.

9. In a heel trimming machine having a rotatable cutter head comprisinga first clamping member mounted on a drive shaft, and a second clampingmember spaced from and movable axially toward said first clampingmember, a plurality of-- curved cutting blades removably mounted betweenthe clamping members and adjustable radially of the cutter head alongsymmetrical guideways formed on theelamping member eccentrically to theaxis of rotation ofthe cutter head, an annular ring movable axiallywithinthe. first clamping member, a plurality of blade positioningmembers associated one with each blade and pivotally secured to theannular ring at points angularly spaced'equally from each other, afinger portion on each positioning member engageable with the cuttingedge of its associated blade, first resilient means for urging saidannular ring and positioning members axially of the cutter head towardthe blades, second resilient means for urging the: finger portionsradially of the cutter head into the path of adjustment of the blades tolimit their adjustment, whereby all of the cutting edges may beaccurately located at points equidistant from the axis of rotation ofthecutter head, and retracting means operable in response to. rotationof the cutter head to withdraw the finger portions from engagement withthe blades and retract the positioning'memberswithin the first clampingmember, said retracting means comprising a plurality of balls within thefirst clamping member and engageable with a, conical bearing surfaceformed on the annular ring, said balls being movable by means ofcentrifugal force to urge: said annular ring and positioning members ina direction opposite to the direction of force of said first resilientmeans, and: a cam face on the first clamping member cngageable with eachfinger portion to move said finger portion. radially inward asthepositioning members are retracted.

1-0.; Ina heel trimming machine, a rotatable cutter head mounting aplurality of cutting blades adjustable radially of its axis of rotation,and positioning means automatically efiective when the cutter head is atrest to engage the cutting edge of each blade to locate all of saidcutting edges at points equidistant from the axis of rotation, saidpositioning means being inefiective when said cutter head is rotated.

References Cited in the file of this patent UNITED STATES PATENTS406,582 Harrigan July 9, 1889 10 Glidden et a1. Sept. 12, 1893 Vose Oct.1, 1895 Busell June 21, 1910 McDowell May 6, 1913 Noon Apr. 28, 1914Mayo July 28, 1914 Harrold Sept. 21, 1915 Fowler Apr. 8, 1930 Taft Oct.27, 1931 Ballatine Feb. 15, 1955

